1 //===-- XCoreFrameLowering.cpp - Frame info for XCore Target -----*- C++ -*-==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains XCore frame information that doesn't fit anywhere else
13 //===----------------------------------------------------------------------===//
16 #include "XCoreFrameLowering.h"
17 #include "XCoreInstrInfo.h"
18 #include "XCoreMachineFunctionInfo.h"
19 #include "llvm/Function.h"
20 #include "llvm/CodeGen/MachineFrameInfo.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineInstrBuilder.h"
23 #include "llvm/CodeGen/MachineModuleInfo.h"
24 #include "llvm/CodeGen/MachineRegisterInfo.h"
25 #include "llvm/CodeGen/RegisterScavenging.h"
26 #include "llvm/Target/TargetData.h"
27 #include "llvm/Target/TargetOptions.h"
28 #include "llvm/Support/ErrorHandling.h"
32 // helper functions. FIXME: Eliminate.
33 static inline bool isImmUs(unsigned val) {
37 static inline bool isImmU6(unsigned val) {
38 return val < (1 << 6);
41 static inline bool isImmU16(unsigned val) {
42 return val < (1 << 16);
45 static void loadFromStack(MachineBasicBlock &MBB,
46 MachineBasicBlock::iterator I,
47 unsigned DstReg, int Offset, DebugLoc dl,
48 const TargetInstrInfo &TII) {
49 assert(Offset%4 == 0 && "Misaligned stack offset");
51 bool isU6 = isImmU6(Offset);
52 if (!isU6 && !isImmU16(Offset))
53 report_fatal_error("loadFromStack offset too big " + Twine(Offset));
54 int Opcode = isU6 ? XCore::LDWSP_ru6 : XCore::LDWSP_lru6;
55 BuildMI(MBB, I, dl, TII.get(Opcode), DstReg)
60 static void storeToStack(MachineBasicBlock &MBB,
61 MachineBasicBlock::iterator I,
62 unsigned SrcReg, int Offset, DebugLoc dl,
63 const TargetInstrInfo &TII) {
64 assert(Offset%4 == 0 && "Misaligned stack offset");
66 bool isU6 = isImmU6(Offset);
67 if (!isU6 && !isImmU16(Offset))
68 report_fatal_error("storeToStack offset too big " + Twine(Offset));
69 int Opcode = isU6 ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
70 BuildMI(MBB, I, dl, TII.get(Opcode))
76 //===----------------------------------------------------------------------===//
77 // XCoreFrameLowering:
78 //===----------------------------------------------------------------------===//
80 XCoreFrameLowering::XCoreFrameLowering(const XCoreSubtarget &sti)
81 : TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 4, 0),
86 bool XCoreFrameLowering::hasFP(const MachineFunction &MF) const {
87 return DisableFramePointerElim(MF) || MF.getFrameInfo()->hasVarSizedObjects();
90 void XCoreFrameLowering::emitPrologue(MachineFunction &MF) const {
91 MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
92 MachineBasicBlock::iterator MBBI = MBB.begin();
93 MachineFrameInfo *MFI = MF.getFrameInfo();
94 MachineModuleInfo *MMI = &MF.getMMI();
95 const XCoreRegisterInfo *RegInfo =
96 static_cast<const XCoreRegisterInfo*>(MF.getTarget().getRegisterInfo());
97 const XCoreInstrInfo &TII =
98 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
99 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
100 DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
103 bool Nested = MF.getFunction()->
104 getAttributes().hasAttrSomewhere(Attribute::Nest);
107 loadFromStack(MBB, MBBI, XCore::R11, 0, dl, TII);
110 // Work out frame sizes.
111 int FrameSize = MFI->getStackSize();
112 assert(FrameSize%4 == 0 && "Misaligned frame size");
115 bool isU6 = isImmU6(FrameSize);
117 if (!isU6 && !isImmU16(FrameSize)) {
118 // FIXME could emit multiple instructions.
119 report_fatal_error("emitPrologue Frame size too big: " + Twine(FrameSize));
121 bool emitFrameMoves = RegInfo->needsFrameMoves(MF);
123 // Do we need to allocate space on the stack?
125 bool saveLR = XFI->getUsesLR();
126 bool LRSavedOnEntry = false;
128 if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
129 Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
130 MBB.addLiveIn(XCore::LR);
132 LRSavedOnEntry = true;
134 Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
136 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
138 if (emitFrameMoves) {
139 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
141 // Show update of SP.
142 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
143 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
145 MachineLocation SPDst(MachineLocation::VirtualFP);
146 MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
147 Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
149 if (LRSavedOnEntry) {
150 MachineLocation CSDst(MachineLocation::VirtualFP, 0);
151 MachineLocation CSSrc(XCore::LR);
152 Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
156 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
157 storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4, dl, TII);
158 MBB.addLiveIn(XCore::LR);
160 if (emitFrameMoves) {
161 MCSymbol *SaveLRLabel = MMI->getContext().CreateTempSymbol();
162 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLRLabel);
163 MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
164 MachineLocation CSSrc(XCore::LR);
165 MMI->getFrameMoves().push_back(MachineMove(SaveLRLabel, CSDst, CSSrc));
171 // Save R10 to the stack.
172 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
173 storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4, dl, TII);
174 // R10 is live-in. It is killed at the spill.
175 MBB.addLiveIn(XCore::R10);
176 if (emitFrameMoves) {
177 MCSymbol *SaveR10Label = MMI->getContext().CreateTempSymbol();
178 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveR10Label);
179 MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
180 MachineLocation CSSrc(XCore::R10);
181 MMI->getFrameMoves().push_back(MachineMove(SaveR10Label, CSDst, CSSrc));
183 // Set the FP from the SP.
184 unsigned FramePtr = XCore::R10;
185 BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr)
187 if (emitFrameMoves) {
188 // Show FP is now valid.
189 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
190 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
191 MachineLocation SPDst(FramePtr);
192 MachineLocation SPSrc(MachineLocation::VirtualFP);
193 MMI->getFrameMoves().push_back(MachineMove(FrameLabel, SPDst, SPSrc));
197 if (emitFrameMoves) {
198 // Frame moves for callee saved.
199 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
200 std::vector<std::pair<MCSymbol*, CalleeSavedInfo> >&SpillLabels =
201 XFI->getSpillLabels();
202 for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
203 MCSymbol *SpillLabel = SpillLabels[I].first;
204 CalleeSavedInfo &CSI = SpillLabels[I].second;
205 int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
206 unsigned Reg = CSI.getReg();
207 MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
208 MachineLocation CSSrc(Reg);
209 Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
214 void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
215 MachineBasicBlock &MBB) const {
216 MachineFrameInfo *MFI = MF.getFrameInfo();
217 MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
218 const XCoreInstrInfo &TII =
219 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
220 DebugLoc dl = MBBI->getDebugLoc();
224 // Restore the stack pointer.
225 unsigned FramePtr = XCore::R10;
226 BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
230 // Work out frame sizes.
231 int FrameSize = MFI->getStackSize();
233 assert(FrameSize%4 == 0 && "Misaligned frame size");
237 bool isU6 = isImmU6(FrameSize);
239 if (!isU6 && !isImmU16(FrameSize)) {
240 // FIXME could emit multiple instructions.
241 report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
245 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
249 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
250 FPSpillOffset += FrameSize*4;
251 loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
253 bool restoreLR = XFI->getUsesLR();
254 if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
255 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
256 LRSpillOffset += FrameSize*4;
257 loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
261 // Fold prologue into return instruction
262 assert(MBBI->getOpcode() == XCore::RETSP_u6
263 || MBBI->getOpcode() == XCore::RETSP_lu6);
264 int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
265 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
268 int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
269 BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
274 bool XCoreFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
275 MachineBasicBlock::iterator MI,
276 const std::vector<CalleeSavedInfo> &CSI,
277 const TargetRegisterInfo *TRI) const {
281 MachineFunction *MF = MBB.getParent();
282 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
284 XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
285 bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);
288 if (MI != MBB.end()) DL = MI->getDebugLoc();
290 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
291 it != CSI.end(); ++it) {
292 // Add the callee-saved register as live-in. It's killed at the spill.
293 MBB.addLiveIn(it->getReg());
295 unsigned Reg = it->getReg();
296 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
297 TII.storeRegToStackSlot(MBB, MI, Reg, true,
298 it->getFrameIdx(), RC, TRI);
299 if (emitFrameMoves) {
300 MCSymbol *SaveLabel = MF->getContext().CreateTempSymbol();
301 BuildMI(MBB, MI, DL, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLabel);
302 XFI->getSpillLabels().push_back(std::make_pair(SaveLabel, *it));
308 bool XCoreFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
309 MachineBasicBlock::iterator MI,
310 const std::vector<CalleeSavedInfo> &CSI,
311 const TargetRegisterInfo *TRI) const{
312 MachineFunction *MF = MBB.getParent();
313 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
315 bool AtStart = MI == MBB.begin();
316 MachineBasicBlock::iterator BeforeI = MI;
319 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
320 it != CSI.end(); ++it) {
321 unsigned Reg = it->getReg();
322 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
323 TII.loadRegFromStackSlot(MBB, MI, it->getReg(), it->getFrameIdx(),
325 assert(MI != MBB.begin() &&
326 "loadRegFromStackSlot didn't insert any code!");
327 // Insert in reverse order. loadRegFromStackSlot can insert multiple
340 XCoreFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
341 RegScavenger *RS) const {
342 MachineFrameInfo *MFI = MF.getFrameInfo();
343 const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
344 bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
345 const TargetRegisterClass *RC = XCore::GRRegsRegisterClass;
346 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
348 MF.getRegInfo().setPhysRegUnused(XCore::LR);
350 bool isVarArg = MF.getFunction()->isVarArg();
353 // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
354 FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0, true);
356 FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment(),
359 XFI->setUsesLR(FrameIdx);
360 XFI->setLRSpillSlot(FrameIdx);
362 if (RegInfo->requiresRegisterScavenging(MF)) {
363 // Reserve a slot close to SP or frame pointer.
364 RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
369 // A callee save register is used to hold the FP.
370 // This needs saving / restoring in the epilogue / prologue.
371 XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
377 void XCoreFrameLowering::
378 processFunctionBeforeFrameFinalized(MachineFunction &MF) const {